Design Microsoft Azure Infrastructure Solutions (AZ-305) interview questions

Right-size resources, use autoscale so you pay for what you use, choose reservations/savings plans for steady baselines and Spot for interruptible work, pick the correct storage tier and lifecycle rules, and put cost gates (Budgets, Advisor, tagging) in place. Model cost against the RTO/RPO so reliability and spend are a deliberate trade-off.

Start from the app and the team. Functions for event-driven, short, bursty work. App Service for standard web apps/APIs that want managed scaling and slots. AKS when you already have containers and need orchestration, service mesh or fine control. VMs only when you need full OS control or a lift-and-shift. Favor the most managed option that meets the requirements.

Pick a real failure and own it without blaming others. Describe how you contained the impact, communicated honestly, fixed the root cause (not just the symptom), and added a safeguard — a test, a monitor, a checklist, a runbook — so it cannot recur. Interviewers want accountability and a blameless, learning mindset, not a claim that you never fail.

Be specific and show it is a habit: hands-on labs and home projects, following release notes and a few trusted sources, a certification roadmap, reading other people’s code or post-mortems, and teaching others to cement what you learn. Tie it to this role’s stack. Enthusiasm plus a concrete routine beats a vague "I love learning".

For production use ExpressRoute for private, high-bandwidth, predictable connectivity, with a site-to-site VPN as failover. Segment with a hub-and-spoke topology, put shared services and firewalls in the hub, and use private endpoints so PaaS traffic never traverses the public internet.

Store secrets, keys and certificates in Azure Key Vault, give apps access with managed identities (no credentials in code or config), restrict the vault with private endpoints and RBAC, enable soft-delete and purge protection, and rotate secrets automatically. Never commit secrets to source control.

Define RTO and RPO first. For HA within a region use availability zones and zone-redundant services. For DR across regions use Azure Site Recovery for VMs, geo-redundant storage (GRS) for data, and paired regions. Automate failover and test it regularly — a DR plan that is never tested does not exist.

Show that you separated the person from the problem. Explain how you listened to their reasoning, brought data or a small proof of concept instead of opinions, looked for the shared goal (reliability, deadline, cost), and either reached agreement or disagreed-and-committed to the team’s decision. Avoid blaming; emphasise the outcome and the relationship staying intact.

Azure SQL Database (PaaS) for new or modern apps that need a single database or elastic pool with minimal management. Managed Instance for lift-and-shift of on-premises SQL that needs instance-level features (SQL Agent, cross-database queries, CLR). SQL on a VM only when you need OS-level control or a feature the PaaS tiers do not support.

Send platform and resource logs to a Log Analytics workspace, instrument applications with Application Insights, build dashboards and workbooks, and set alerts on the signals that matter (availability, latency, errors, cost). Use Azure Monitor and Service Health for platform issues, and keep logs long enough to meet compliance.

Lead with the impact in their terms (cost, risk, time, customers affected), not the technical cause. Use a simple analogy, avoid jargon, and offer a clear recommendation with options and trade-offs. Confirm they have understood and tell them what you need from them. The goal is a confident decision, not to show how much you know.

Managed disks back VMs and need block storage. Azure Files gives an SMB/NFS share for lift-and-shift apps and shared access. Blob storage is for unstructured objects, backups, media and data-lake workloads, with access tiers (hot/cool/archive) and lifecycle rules to control cost. Match the access pattern and protocol to the service.

Connect your answer to the actual job and company: what about the work, the stack or the mission fits your strengths and goals. For the three-year question, show healthy ambition and direction (deeper expertise, more ownership, perhaps leading) that the company could realistically support, so it reads as commitment, not a stepping stone.

Set a cadence and a single source of truth: short, regular updates in plain language with status, impact, next step and ETA — even when the news is "no change yet". Tailor the detail to the audience and never let people find out bad news late. Reliable, proactive communication builds the trust that lets you do the technical work.

Explain how you gathered the facts you could quickly, identified the biggest risk, made a reversible decision where possible, and set a point to re-evaluate. Note how you communicated the uncertainty and your assumptions. Show judgement and bias for action — making a sound call and adjusting beats waiting for perfect information.

Protect the business first: a production outage affecting users usually wins. State your rule — impact and urgency over who is shouting loudest — communicate quickly to set expectations, delegate or ask for help, and park or renegotiate the lower-impact items with their owners. Show calm, a clear framework, and that you keep people informed.

Use a management-group hierarchy that mirrors the organization, assign Azure Policy and RBAC at the right level so they inherit down, standardize tags for cost and ownership, and use Azure Blueprints or landing zones to deploy consistent, compliant subscriptions. Centralize identity in Microsoft Entra ID with PIM for just-in-time admin access.

Give a concrete example: how you set clear expectations, paired on real work, let them struggle productively before stepping in, gave specific feedback, and gradually handed over ownership. Mention a result — they shipped something, passed a certification, became independent. Leadership is about multiplying others, not doing it all yourself.

Use the STAR method: briefly set the Situation and Task, then spend most of your answer on the Action — how you broke the problem down, what you tried, how you tested — and finish with the Result and what you learned. Pick a real example with a measurable outcome (time saved, outage resolved) and show your reasoning, not just the fix.

Azure Cosmos DB — it offers turnkey global distribution, multiple consistency levels, single-digit-millisecond latency and multi-region writes. Choose the consistency level (strong → eventual) that balances correctness against latency and availability for the workload.